1. Field of the Invention
The present invention mainly relates a power supply device that can supply electric power to an electric motor for vehicle traveling, a power supply device that can be charged with electric power generated by natural power sources such as solar batteries or with midnight electric power, and a power supply device suitable as blackout backup power supplies that are suitably prepared for a blackout. The present invention more particularly relates to a power supply device that can estimate standardized available output power, which varies with the time, under the conditions that temperature and SOC are constant, and a vehicle that includes this power supply device.
2. Description of the Related Art
Battery standardized available output power varies with the time. Available battery electric power will decreases with battery deterioration. On the other hand, the available electric power also varies with SOC and temperature. For this reason, if a device estimates standardized available output power of a battery, the device is required to estimate available output power and to detect SOC and temperature at the estimation, which influence the available output power.
If a battery is controlled in charging and discharging operations in the suitable state, available battery output power can be high with suppression of deterioration. For example, in the case where the battery is controlled so that the available battery output power can be reduced in charging and discharging operations with battery deterioration, the life span of the battery can be longer. It is very important for large capacity power supply devices such as vehicle power supply device and natural power storage device to increase their battery lives. The reason is that a number of large capacity batteries are used for high output power, which in turn increase facility cost, and that high output power is required. If a battery of a power supply device is charged/discharged in a certain condition without consideration of available output power of the battery, deteriorated batteries may be sharply further deteriorated when charged/discharged with high electric power, or even in the case where its available output power is adjusted low, the battery life can be long but the battery cannot supply suitable electric power to loads. Accordingly, problems will arise. In order to increase battery life, and to supply loads with electric power as high as possible, it is important to accurately estimate standardized available battery output power, which varies with the time.
A device has been developed which estimates available output capacity of a battery (see Japanese Patent Laid-Open Publication No. JP 2001-203,935 A).
The device disclosed in this Literature detects voltage of the battery to obtain difference voltage values between the detected voltage value and upper and lower limit voltage values of the battery, and an internal resistance value of the battery to estimate the amount of increase/decrease of a current required for a voltage of the battery to agree with the upper and lower limit voltage values based on the internal resistance value and the difference voltage values whereby estimating available output power based on the estimated amount of increase/decrease of a current.
Since the aforementioned device disclosed in the Literature estimates available output power, this device can estimate standardized available output power of the battery based on the available output power. However, available battery output power varies with temperature, SOC, and the like. For this reason, it is necessary to estimate the standardized available battery output power under the conditions that temperature and SOC are specified values. For example, the battery status is estimated under the conditions of standard temperature of 25° C. and standard SOC of 50%. However, in practical use, battery temperature varies and rarely agrees with the standard temperature, and SOC also varies and rarely agrees with the standard SOC. If standardized available output power of a battery is estimated not under the conditions of the standard temperature and the standard SOC but of actual temperature and SOC where the battery is actually charged/discharged, although available output power values can be estimated under similar conditions, the available output power values cannot be accurately compared with each other under the accurately same conditions.
The present invention has been developed for solving the disadvantage. It is an important object of the present invention to provide a power supply device that detects temperature and SOC of a battery to be charged/discharged under the conditions that the temperature and SOC rarely agree with standard temperature and standard SOC, and can estimate standardized available output power under the standard conditions of the battery, and a vehicle that include this power supply device.
In addition, it is another important object of the present invention to provide a power supply device that detects internal resistance and temperature of a battery under the conditions that the temperature and SOC of the battery rarely agree with standard temperature and standard SOC, and can estimate standardized available output power of the battery under the conditions of the standard temperature and the standard SOC whereby accurately detecting the standardized available output power of the battery under the same conditions that the temperature and SOC are standard temperature and standard SOC.